[Milsurplus] Fwd: Advice on which caps to keep ( even longer )

[mstangelo at comcast.net]

Before I use any capacitors I check them out with a Hallicrafters AC-1 capacitance bridge, the oldest piece of test equipment in my shack, and a DE-5000 RLC meter, which is one of the newest pieces of equipment in the shack.

I like the AC-1 because I can measure leakage current up to 500 volts. The DE-5000 allows me to measure ESR which is essential for electrolytic capacitors.

I have a bunch of ElMenco postage stamp capacitors with values of 200 and 270 pF. I sampled a couple of them and they show no leakage at 500 volts with the AC-1 The Q and ESR are in the range of new mica capacitors on the DE-5000 so I will keep these capacitors.

The DE-5000 tests up to 100kHz so I use my NanoVNA to characterize the capacitors at the operational frequency.

When I assemble coaxial cables I use the AC-1 voltage leakage function as a hi-pot tester to check for shorts.

Another test I do is to check the solderability of the leads. I had a drawer full of polystyrene capacitors. I wanted to use some in a filter but found out the leads will not take solder. The leads are apparently solder plated steel and the steel rusted causing sever corrosion. I had to throw out about half of the caps.

Mike N2MS